"Extremely easy to do manually and stable."
It is only because my 160 and 80 m OCFD is being modified frequently that I
decided to develop the auto trainer. It takes multiple actions to tune a
single bin and there are 20 bins for 160 m. If a multi-step task needs to be
done infrequently the
"I would then question the electrical stability of the 160M antenna. In other
words, why and what is changing?"
I change it. Changes include the total length, feed point position, and the
feed point matching L and C values. It's an experimental antenna.
One would not expect to make many D
I've had my KAT500 for about 18 months and I thought I had come to know it
quite well. Today I found something that surprised me.
The KAT500 utility has 2 "Memory Recall on Tune" options, one for MAN mode and
one for Auto mode. My understanding was that, if these options were not
enabled, the
December 17, 2019 I posted the following"
"I've had my KAT500 for about 18 months and I thought I had come to know it
quite well. Today I found something that surprised me.
The KAT500 utility has 2 "Memory Recall on Tune" options, one for MAN mode and
one for Auto mode. My understanding was
Please ignore previous post. It was inadvertently send before editing was
complete.
Andy, k3wyc
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Sorry for the inadvertent premature posting. I'll try again -
After I had posted my observations on the behavior of KAT500 "Tune on QSY"
option I suggested to an owner of a TS-890S, KAT500, and KPA500 that he should
try disabling the QSY option as it might cure his annoying re-tunes during
t
A few years ago I ran a series of CW keying tests on my Kenwood TS-590S. I
found that, when configured for full break-in, the RX did not have time to
"wake up" at speeds faster than about 26 wpm even though T/R switching
completed much faster than that. Based on that test data I abandoned full
"With switching mode powersupplies (as in the KPA500 and 1500 and most of the
solid state amplifiers with ps included) usually no further measures are
necessary or would help in that respect as most SMPS have soft start circuits
included."
KPA500 nominal 60 V PSU is not a switching mode supply.
"On key down (input of 15W) the asterisk briefly displays, then display changes
to 18.1, back to HV display on key up."
Are you saying the "HV" text in the display goes away or that it reads HV 18.1?
Normally the HV display continues to read the PA supply voltage regardless of
whether the amp
As a follow up to my previous message I measured PA voltage and current for
OPER mode not keyed and OPER mode keyed with no RF drive input.
PAI not keyed .0, keyed .2
PAV not keyed 80.9, keyed 77.8
Hi reflected power fault can't happen with no drive so won't influence the
results.
Andy
"Basically, based on Bob's measurements, the power dissipated is fairly
independent of drive level. So, running at reduced power really isn't stressing
anything any more that full output."
I have done quite extensive testing of my KPA500 and provided links to my
results. My KPA500 PA dissipati
"It's heat that stresses the transistors, not efficiency. The numbers show more
dissipation with increasing power level."
Which number show that? My test data for the KPA500 are very clear. Peak PA
dissipation for any given load is at about half power output.
Andy, k3wyc
__
I had one off-line request for my test data so I'll share a link:
https://www.dropbox.com/s/uf258k1nw8o7xw3/Evaluation%20KPA500%20PA%20Dissipation%20rev%20ad4.pdf?dl=0
I have previously shared other links to reports that are based on the same raw
data set.
Please note that the plots in this rep
"I am seeing a lot of confusion and erroneous conclusions based on the terms
'efficiency', 'dissipation' coupled with 'power output'."
Yes, very true. Only a few have actually contributed test data. All the rest
is assumption and speculation.
Andy, k3wyc
__
Doug,
"I would like to know if running 2/3, 1/2 or even 1/4 maximum power output
increases reliability and MTBF."
I have no experience of amplifier design but I would expect reliability of the
finals to depend on temperature. Finals temperature will depend on the power
dissipated in the fina
"I understand that efficiency decreases as one derates from the maximum of
1500W output.It surprises me that the power dissipated would peak at half power
output or 750 Watts."
I have no test data for the KPA1500 and will not speculate on the shape of the
PA dissipation curves. All I have is d
"This is probably what folks are thinking of when they assume maximum
dissipation occurs at less than full output."
A possible source of error in my data is that the dummy load is cool at the
start of the power ramp and hot by the time peak power is reached. I recorded
LP-100A data during ea
"What is happening. ? How can I clear this from happening?"
Do you have anything connected to the KPA500 "RS-232 PC" serial port? When my
KPA500 went into loader mode I traced the problem (with help from Jack) to
corrupted RS-232 data that was being interpreted as the KPA500 loader command.
It's probably worth emphasizing that the KPA500 is only vulnerable to a
spurious "D" command when it is in "powered but off" state. Perhaps the
problem can be avoided by changing the sequence of remote station power up so
KPA500 is only powered when the server is stable. It may also help to l
Good to know I wasn't the only one wanting to do this. In my case I wanted to
make my TS-590S beep if power was manually set above my controller's programmed
band max power limit. I force the power setting back to max and beep. It was
hard to find a way to make the TS-590S beep but I eventual
I recently had an intermittent high noise level on 6 m band and there seemed to
be a correlation with activity at my neighbors house. I ran a PC application
that showed my transceiver's S meter and remoted my PC desktop to my Android
phone with TeamViewer.
Next time my neighbor was working in
"I have a KPA500 and the protection circuit works well, but I was wondering
what can be done to add an extra layer of protection?"
One approach is to use a micro-controller to manage the KPA500 and KPA500.
However, most would rather avoid the additional complexity and the, not
insignificant, d
The KAT500 has continuous frequency coverage for saving and selecting tuning
solutions and is not constrained to amateur band limits. However, the antenna
selection can only be defined for the amateur bands.
Does the KAT500 simply use the antenna selection defined for the amateur band
closest
"Also keep in mind that tuning it on "off band" frequencies requires that you
transmit a signal of at least a minimal value ... which is technically not
legal."
No that's not true. The KAT500 can be set to any frequency within its
operating range by sending it the frequency on the serial bus u
"I didn’t say “set the operating frequency.” I said “tuning it.”
I have complete manual control over L, C, and C side without transmitting. I
can, therefore, set a tuning solution for any frequency bin within the KAT500
frequency range without transmitting. I can also recall a stored tuning
s
"Well there is one exception to the idiot-proofing and that occurrs if you use
macros that have the PCxxx command in them for setting power. Under certain
conditions if a PCxxx command is used in a macro it can overide the CONFIG:PWR
SET Per bAnd setting. I have removed all PCxxx commands from
"The misconception is that there are presets and there are NOT, the K3s stores
the last set power for that band/Amp Mode. The "presets" are the last power
setting the operator made either manually or via software/macro based on the
amplifier mode (OPER/STBY). IF you adjust the K3s power then y
"Once the correct power value is set for the amp in OPER mode and for the
individual band, I find no need to change the power setting. If one has it
correct... then changing it would seem to make it no longer correct. This
makes no sense to me."
Your concept seems to be that the correct p
"How difficult would it be to implement a power limit option through firmware
to prevent exceeding per-band drive levels when the amp is on?"
>From what I have heard about Elecraft's power management scheme it would not
>be difficult at all. However, writing the code is only a small part of
>
"The effect of SWR on the amplifier, of course, depends on the actual impedance
at the amplifier, so in some cases it may be more or less sensitive to SWR."
My limited experience with solid state amplifiers make me believe that
characterizing the load by "SWR" is not very useful. The measuremen
"> Each “bin” has room for 6 ATU settings. Each of these 6 ATU settings
> contains bits for the ATU relays (L, C, side, ATU bypass and ANT relays)
> plus an SWR measured when the ATU was bypassed. The antenna number (ANT
> relay bit settings) is included in the ATU setting, so we don’t need to
My 3rd edition RSGB Amateur Radio Handbook dated circa 1965 includes, on pages
387-388, a section on "The G5RV 102 ft Dipole". It includes a description of
how the antenna should be configured and how it works for each of the following
bands - 1.8 Mc/s, 3.5 Mc/s, 14 Mc/s, 21 Mc/s, and 28 Mc/s
"I have no information one way or the other, but I suspect the KPA1500 also
suffers from this issue."
To the best of my knowledge KPA1500 extracts the TX frequency from IF, FA, and
FB just like the KPA500 does. I do not believe it has the "FA only" limitation
of the KAT500.
73,
Andy, k3wyc
__
"Neither the Kenwood TS-890S User Manual nor the Kenwood TS-890S In-Depth
Manual make mention that their VFO’s A and B implement slightly different
character streams."
The implementation of FA and FB character streams is identical except for the
use of "B" instead of "A". Both reliably and con
" I also think that I could build a modified null modem for the KPA500 with a
couple of diodes to connect the KAT500 RX input and KPA500 RX input in
parallel. Then, when the KPA500 polls for frequency info both the KPA and KAT
will get the data. Sounds like a good "shelter in place" project. Bri
"the prosign for "Please repeat,"or "I will repeat."
I was taught over 55 years ago that "repeat" was an artillery fire control
instruction that had no place in any communication except for artillery fire
control. Surprising to me that IMI would be defined that way.
In UK Signals, the phone p
When the KAT500 trips a fault the fault light is lit but, unlike KPA500, there
is no front panel indication of which fault is active. One would expect the
KAT500 Utility to display information on the active fault but it does not.
E.g. -
KAT500 Utility (for Windows) ver 1.19.8.5 displays "No F
"I realized that operating today in WPX that the temp was reading over 43 c
and no fans."
At what temperature did you expect the fans to start? KPA500 switches fans on
at 50 deg C.
Wouldn't the temperature readout be derived from the same thermistor that
provides temperature for fan control?
"Does "100% - 10 min, 100 W key-down" mean that if you key down without stop in
CW mode it can go 10 minutes at 100 watts? That seems like an awful lot."
If you want to know what it actually means you'd probably have to run a test
and record the PA temperature. Does it reach maximum value withi
"With high power is it your practice to start with lower levels and work your
way up or do you go for broke from the start?"
For FT8 I make the initial call with the power that I think is required for the
propagation path. If the station replies I may increase or reduce power based
on their re
"No hum using a dummy load.
No hum using a dipole.
Hum only with my all band vertical."
I don't understand how that information results in "problem solved". The
problem didn't go away.
It could perhaps be RFI but isn't it more likely that the hum is dependent on
the load presented by the anten
"The AM radio in the car works fine in the driveway, but as soon as one starts
to enter the garage, reception is covered up by a loud growl of static. Radios
in a room adjacent to the garage and over the cable in the basement below also
have a problem while AM radios at the other end of the hous
"The mechanism whereby a coax feedline is carrying RF current into our shack
producing hum is that the current couples into electronics (usually by a Pin
One Problem) and changes the bias state of some gain stage."
My understanding of the original post is that hum was heard in the shack and
tha
"So rest easy, if you were ever concerned about the clicking and clacking and
what it might be doing to the quality of the relays. They will probably out
last the K3 and certainly you."
The key word in MTBF is "mean". How lucky do you feel?
Relay failures, especially in tuners, can give faults
"After transmitting at 200W the temperature slowly
rises above 60 degrees C, but the fan doesn't cut in. Does anyone know
if this is normal behavior and what temperatures I should expect to see?"
Nominal temperature for start of fan speed 1 is 50 deg C although my data for
one test run showed s
"60 deg C with fan not running is not normal. 60 deg C is the nominal
temperature for start of fan speed 3."
The conversation was continued off "list" but there are a few points that I'd
like to be in the archive -
There would appear to be two possible failure conditions. Either the fan is
"Found out also that there is a brocken pin at the PA board at jumper at P68A
male connector. This brocken pin still remains in the according female
connector. So lots of problems."
I don't know this module but Elecraft "keys" some connectors by removing a male
pin and plugging the correspondin
"All other front panel stuff works I suspect the buttons for the menu pwr
current and temp work also but I cant tell since the lcd only shows test
pattern."
The KPA500 display will show what looks like a test pattern if menu item LCD
ADJ is set to 100. If it used to work you may have accidental
Given that the "test pattern" may be caused by an extreme LCD contrast setting
I'd suggest checking the contrast voltage that is derived from PWM signal
VCONTRAST.Contrast voltage is available of "TP2" which is connected to LCD
pin 55 (VLCD).
The schematic shows VLCD range is 3 - 6.5 V. I
"Can anyone recommend a safe polish or other to aid in buffing out a minor
surface scratch on the plastic (Perspex/acrylic?) screen cover"
Meguiar's Mirror Glaze MGH-17.
I have used it on aircraft and other transparencies. Deep scratches may
require work with increasingly fine abrasives. MGH-
"At 100 the LCD segments will be shown as grey, but the value should be
readable, although it may be difficult to distinguish the exact segments that
should be illuminated. There is not much contrast between the grey segments and
the black ones."
While I was experimenting with contrast settings
Hi Jack,
Just for future reference - Does loading a previously saved config file
restore all settings that were reset by powering up with EDIT pressed?
Thanks and 73,
Andy, k3wyc
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KAT500 leaves unselected antenna ports open circuit and defaults to port 1 when
power is removed. The relays are not latching.
I don't have details for the KPA1500 but the ATU board photos available here -
https://fccid.io/UTR-KPA1500 - have high enough resolution to trace the
output signal
"At a distance of only six feet to your antenna, perhaps your amplifier is
trying to warn you that you may also have a human RF safety issue. "
Well, do you feel warm
We do what we must to get a signal out. My 40 m dipole is in the attic of a
single story house under an asphalt and fibregl
"A very close 40 meter antenna is much safer than a close 12 or 10 meter
antenna "
I used to teach the RF safety class for our club's extra and general course
students. Most people in the Extra course were already General and almost none
of them had ever conducted an RF safety evaluation. I d
"I got the report that my CW sounds just fine until the amp is in line. Then it
is described as "some kind of artifact... like a bell sound... like a delay."
This is consistent with the other report I had been getting of a "ringing,
bell-like" note to my CW. This is most apparent at 30 wpm, as I
"In general, ALC between an amp and a rig is a recipe for clicks and splatter.
Most authorities advise against using it. This is not new -- it's in the manual
for Ten Tec legal limit amps from the late '70s and for every amp I've owned
since."
The OP has a KPA500 and K3S interconnect by an Elec
"So, it seems like the amp is not sensing the RF frequency coming out of the
KX2 - but why?"
If the KPA500 is sensing RF frequency it will display the appropriate band on
its display. Does it?
Loss of RX signal could be caused by failure of the KPA500 T/R switch or it
could always be selected
"Why does the KPA500 suck air from the top vents and blow it out the back"
I asked quite a while ago what thermal analysis had been performed on the
KPA500 and got no answer here. It would seem reasonable for the fan to
augment natural convection rather than oppose it.
Kenwood built a batch o
I don't think anyone was proposing taking on a new cooling design for the
KPA500. The heat sink is there. The conduction path between the finals and
the heat sink is what it is. The fan is selected and the fan speed
temperatures are defined. The only speculation is whether the flow direction
"It is interesting to hear how others experience their KPA500s over various
conditions."
I have over a years's worth of KPA500 data recorded but it takes some effort to
run it through the Excel templates to make pretty plots.
My KPA500 temperatures are strongly influenced by ambient temperature
When considering the upper temperature limit of a KPA500 I think it is
important to know if, for the planned operating condition, the temperature
limits at a value that the owner is willing to accept. In other words, does
the fan produce sufficient airflow for the temperature to reach its maxi
"Just looked up “AlexLoop” - amazing presentation and price."
More fun to build your own. I work into Asia most mornings on 30 m with mine.
Tuning is not a major problem as the loop capacitor is driven by a geared DC
motor via a pair of bias T. Only a single coax connects the loop to my stati
Well if it were mine I'd open it up and inspect everything between J3 pin 25
and T1. I would expect to find a well toasted resistor but I don't know the
KPA500 well enough to know which one.
I think this is the third report I have seen on this reflector of a KPA500
blown by accidental high pow
"That is a very good argument for having ALC active between the amp and radio. "
ALC is just another reactive protection. In my station the KAT500 is
commanded to inhibit the KPA500 key line by default. Only when all required
conditions are met is the key line enabled. Enabling conditions in
"Can you expand on this setup please? I would like to emulate it."
It's one of the many functions of an Arduino based station controller. I've
been working on a descriptive presentation during the "lock down" and hope to
publish the presentation and code before too long. Fair warning though -
"The Y cable is connected to the SDA 100 Data IN, radio port, points 2 (RXD)
and 5 (ground)"
You also need to link 7 and 9 on the SDA 100 connector. Pin assignments on the
SDA 100 connector are not typical RS-232.
"PINOUT of 9 pin SUBD DATA IN CONNECTOR
1. Data out RXD
2. RXD to RS232 Radio TX
I started down this path because I'm trying to help a Scottish op who seems to
have a failed KPA500 XCVR port. (Scope shows no indication of polling when Ser
Poll is on.)
KPA500 has an IO board with two serial interfaces. One is for connection to a
PC and the other for connection to a transce
"My station is set up exactly as described by Andy below."
"Ive also boneheadely transmitted the TS590 at 100w with the amp enabled. The
amp IMMEDIATELY goes to standby and screeches loudly at me."
A clear indication that your setup is not exactly like mine. My controller
won't let me TX at 10
"Serial IO board K1 is controlled by "SBYB" which traces to signal "BYPRLY".
The names suggest "bypass relay" but under what circumstances is this signal
set/cleared? In other words, when does K1 open the data out line?"
Well I found the answer thanks to another KPA500 owner running a similar
"(More parts = more fun.)"
You must miss the days when tag strip construction was the norm. I prefer the
equipment to be smaller than the room it has to fit in. I also prefer to be
able to lift it. My first commercial RX was an AR-88D and it almost failed
both tests.
Highly integrated cir
"The information sent by the K3(s) is needed, hence the need to connect
(somewhere) to TXD info from the K3(s). "
I suspect that signal name "TXD" may be being misused in this discussion.
Having been caught by this I prefer to use the terms "data out" and "data in".
On a TS-590S COM port pin 2
"If it were mine, I would put the LP700 on the antenna line to monitor what is
going on with the antenna itself."
My LP-100A is between my KPA500 and my KAT500. I want to know what load is
being presented to the KPA500. Neither the KPA500 not the KAT500 can display
complex load values. Sinc
"It would seem to require an internal modification and two additional rear
panel connectors."
FCC photos shows LPF RF Out is a BNC and tuner RF In is a BNC.Should be an
easy mod if there is room on the rear panel for 2 BNC connectors. Perhaps the
LP-700 coupler would fit inside the LP1500
"While the USB cable connected to the computer was loose, it curled around I
accidently kicked it and it slid under the power supply and contacted one of
nuts on the bottom of the power supply and sparked."
The most likely contact scenario would seem to be that the shell of the USB
connector ma
"The most likely contact scenario would seem to be that the shell of the USB
connector made contact with a grounded nut on the power supply. "
I received an email that said Astron power supplies have exposed transistors
that are not at ground potential. That prompted me to investigate the Astro
The field day rules need to be reviewed and corrected, not just for allowed
power sources.
Take this for example -
"3. Date and Time Period: Field Day 2020 will be held June 27-28. Field Day is
ALWAYS the fourth full weekend, beginning at 1800 UTC Saturday and ending at
2059 UTC Sunday.
3.1.
Many Kenwood and Elecraft transceivers support Auto Information mode. When
enabled, AI mode causes the transceiver to output state changes as soon as they
happen rather than waiting to respond to the next periodic poll. AI mode has
the potential to allow an application or external controller
"Just as other appliances sold these days with a motor i.e. washing machines,
dishwashers... while digital control may add nice features, the noise
generated can reduce operator pleasure (or operating hours)."
It's not a new problem. My over 30 year old Maytag washing machine with crude
mecha
"So here is what I determined: with 35 wpm dits (or dahs, it doesn't matter)
from the internal keyer in Full QSK mode, CONFIG TX DLY = 8 (normal), there is
a minimum of 5.6 ms between KEY OUT low and the first whiff of RF. I say
minimum, because there is a certain amount of jitter in the length
"In short, hearing between elements gave us bragging fodder but served no real
practical purpose. "
My interest was from an engineering perspective. I found that, at typical
contest and DX chasing speeds, the TS-590S BDLY-FBK (full break-in) setting
offered no operational advantage. I chose t
"The K3 has only one way to communicate with the KPA500 and KPA1500, that being
Auxbus. There is no communications on this path that allows setting of specific
power levels in the K3 - there is only the OP/STBY that simply selects either
the K3 high power (STBY) or low power (OPER) modes. You ha
"As has been mentioned - shouldn't be too difficult to do this with an external
Arduino based controller. "
My brain needed something to do while I was watching 30 m for new DX so I
created a rough draft proposal for "power per frequency bin". I created this
to stimulate discussion not becaus
"Can you tell me where to start looking?"
A report of a similar event was posted just a few weeks ago. Some of us were
assuming it was a KPA500 failure but it turned out to be a failure of the input
AC voltage.
Is AC power present? Does the KPA500 power up if connected to a known good
power
I use a home brew mag loop on 30 m band and work into Asia most mornings with
it. The loop tunes to a near perfect match (1.00:1 SWR) but becomes instantly
detuned when a dove perches on top of it. SWR jumps instantly to > 3.0:1 and
trips my High SWR monitor.The birds look stupid but they
Dave
Sent: Sunday, June 7, 2020 7:19 AM
To: Andy Durbin
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [OT] Birds and DX
Somehow figure out how to mount a fake owl on top?
Dave wo2x
Sent from my iPad
> On Jun 7, 2020, at 10:16 AM, Andy Durbin wrote:
>
> I use a home brew ma
Ref the linked article - "you slowly tune the received signal until it reaches
the magic tone that means "zero-beat". Usually, this is the same tone as your
CW sidetone, 500-800 Hz, depending on your rig. You need a good ear for pitch."
Has everyone forgotten what to "zero beat" means or is it
"But keep in mind that the KPA Utility will not connect to the KPA500 unless
the amp is first powered on"
That may be a bit misleading. Depends on what you mean by "powered on". I
consider the KPA500 to have 4 states:
Not powered
Powered but off
STBY
OPER
The utility can be connected to KPA
"P can be sent with the Utility "command tester"
or press "ON" on the utility "Operate" page.
BTW - My first reply overlapped with Jack's. In case of conflict believe him
not me.
Andy, k3wyc
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"Who knew there were so many Q-codes :)"
My favorite from my time as a teenager in the cadet force signals wing was QUQ.
I had remembered it as "Shall I point my searchlight at a cloud, occulting if
necessary, in order to pinpoint my position".
Either my memory is playing tricks on me or the m
"ZBM2: "Place a competent operator on watch on this frequency."
Is QLF the more sensitive equivalent??
73,
Andy, k3wyc
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"Most folks assume there will be no delay between KEY closure and KEY OUT
closure, but there is an extra delay (of about 5 ms, minimum) in the K3S."
I suppose I'm not in the "most folks" group. I measured this delay when
investigating the keying characterisitcs of my Kenwood TS-590S. Key down
ACP 131(F) -
https://web.archive.org/web/20130215140321/http://jcs.dtic.mil/j6/cceb/acps/acp131/ACP131F09.pdf
Offered to NATO for adoption:
https://archives.nato.int/uploads/r/null/1/2/127387/SGM-0921-55_ENG_PDP.pdf
Was anyone actually expected to memorize all of these codes?
73,
Andy, k3wyc
"I repeat my advice that keying characteristics must be evaluated in the
FREQUENCY domain (as occupied bandwidth), NOT in the TIME domain
(oscilloscope). The reason has been stated here many times -- it's not only the
TIME of the transition that determines bandwidth, it is the SHAPE of the
tran
I found this quite annoying too. My approach was to try to understand how the
Z bracket temperature varied relative to the heat sink temperature. I placed a
thermistor on the front end of the Z bracket and another on the heat sink fin
closest to the Z bracket. I logged the standard PA tempera
"If you can figure out how to keep the relatively thin "Z" panel from expanding
and contracting as it is heated and cooled, you will have a solution to the
problem."
If the Z bracket really is the source of the noise, and I'm not yet convinced
it is, then there is no need to stop it expanding
I'd like to hear from who has successfully tailored KAT500 serial interface
commands FCCS and FCMD to overcome a frequency stability issue. I cannot
reconcile the results of my experiments with the command descriptions.
Yes, I have a request in with support but the relevant specialist is no
"Someone asked me recently whether a KAT500 could be remote-controlled"
It wasn't me that asked but I have been considering using the KAT500 as a
remote tuner as I need higher power capability than my current MFJ-993BRT.
However, my approach was going to be to buy just the KAT500 board and
fi
"The keying interrupt must be provided by the ATU in order to avoid hot
switching the ATU relays when it tunes. This cannot be determined anywhere but
in the ATU, thus it must provide the break.
That key line break is pretty important to the life of the ATU."
Thanks to Jack and Dick for pointin
hibit is not needed to protect the KAT500.
Andy, k3wyc
From: Jack Brindle
Sent: Saturday, November 3, 2018 12:58 PM
To: ANDY DURBIN
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KAT500 as a remote-controlled tuner
The keying interrupt must be provided b
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